Method for Predicting a Demand for Repair Parts

1. A method for predicting for a demand of repair parts comprising: collecting data of the number of troubles, causes of troubles and the number of years elapsed with respect to a certain kind of repair parts on the basis of said repair parts exchanged owing to troubles within a guarantee period; extracting troubles owing to durability deterioration from said causes of troubles to sum up the number of troubles owing to durability deterioration for each year elapsed; calculating a trouble rate of said repair parts for each year elapsed from said number of troubles summed up for each year elapsed and the number of existing products for each year elapsed; presuming a trouble rate of said repair parts after said guarantee period has elapsed from said calculated trouble rate of said repair parts for each year elapsed; and calculating market scale in future of said repair parts from said presumed trouble rate of said repair parts after said guarantee period has elapsed and a presumed number of said existing products in future to predict a demand for said repair parts.

2. A method for predicting a demand for repair parts as claimed in claim 1 , wherein said trouble rate of said repair parts after said guarantee period has elapsed is presumed by making a Weibull-analysis of said trouble rate of said repair parts for each year elapsed.